Method of manufacturing electrical conductors having a knitted protective jacket



Jan. 1, 1946. M. D. SWARTZ ETAL 2,391,931

METHOD OF MANUFACTURING ELECTRICAL CONDUCTORS HAVING KNITTED PROTECTIVEJACKETS Filed April 4, 1942 INSUZ 4 TING SHEA THING 3 BEA/0E0 .14 CKETWITH 1 1 WIAT/IEE PEOOF/NG ASPHALT IMPEEGNA TIO/V my TING I l v PatentedJan. 1, 1 946 UNITED vSTATES PATENT OFFICE i ME'rnon or MANUFACTURINGuaCrmCar.

CONDUCTORS HAVING A KNITTED rno- TECTIVE JACKET Application April 4,1942, Serial No. 437.676

7 Claims.

The present invention relates primarily to improvements in insulatedconductors provided with an insulating covering, the conductor core alsocarrying a loosely knitted tubular fibrous jacket or sheath, this beingin contradistinction to prior art conductor cores which are providedwith jackets which are tightly and securely braided around the conductorcore.

The substitution of a knitted fibrous jacket, and particularly of thecharacter herein disclosed, for a tightly braided jacket has made itnecessary to provide a special saturant for the tubular knitted jacket,said saturant functioning to adequately bond the tubular knitted fabricsheath to the insulating medium of the conductor core and further tobond threads of the fibrous sheath one to the other so that upon thebending or flexing of the electrical conductor, the insulating coveringis not exposed to the air or to a deteriorating amospheric influence.The saturant composition is applied in a liquid state to the tubularknitted fibrous sheath and cools to a soft pliable adhesive condition.

treated, it may be further processed to apply a dame proofing coating ofstearine pitch and then a color coating, all as well known in the priorart.

It is the primary object or" the present inveu tion to provide a methodof manufacturing an electrical conductor having a conductor Wire, andinsulating jacket thereon, and thereover a tubular knitted protectivejacket, said method comprising heating a saturant to substantiallyremove therefrom all'volatile matter, impregnating the knitted jacketwith the so -treated saturant and adhesively uniting the knitted jacketto the in-= sulated jacket while adhesively uniting the threads of theknitted jacket together so that upon subjecting the so-treated conductorto substantial stresses, the insulating jacket is not exposed todeteriorating atmospheric conditions, said saturant being preferably aplastic resin saturant and, in some cases, having in admixture therewitha thermoplastic cellulose ether com patible with the resin.

It is a further object of the present invention to maintain the saturantor adhesive during the impregnating step at a temperature varyingbetween about l80 F. and about 350 F. The invention will be illustratedin connection with the accompanying drawing, in which: I

' Figure 1 is a plan view showing a conductor provided with a prior artbraided jacket, the latter being impregnated with an asphalt waterproofing composition.

Figure 2 is a diagrammatic representation of the saturating, finishingand polishing apparatus.

Figure 3 is a perspective elevation oi a device Bill After the conductorcore has been so did in which electric conductors made in accordancewith the present invention may be coated with a color coatingcomposition and thereafter dried.

Fisure i is a. plan view illustrating in detail the structure of atubular braided jacket.

Figure 5 is an enlarged view of a conductor provided with a knittedjacket formed of a group of interconnected wales extending spirallyaround the insulating sheath.

' Figure 6. is a detail showing the applicator pot.

Reierring to Fig. 1, the copper wire, identified by the latter A,carries an insulating sheathing B which is preferably rubber, but whichmay be any material that will insulate the copper wire. Thi conductorcore is Provided with a braided jacket C which is impregnated with theusual water proofing saturant or compound D, an asphalt compositionbeing normally used for this purpose. After the tubular braided jackethas been treated with the saturant, there is then usually applied acoating E of a flame retarding and weather proofing material, saidcoating preferably being stearine pitch or a mixture of stearine pitchand other elements, as well known in the prior art. it is quitecustomary to cover the stearine pitch coating E with a color coating F.Thereafter, if desired. there is applied over the color coating F, awax-like coating G1.

An electrical conductor produced as above set forth and using a tubularbraided fabric jacket has proved satisfactory when united to theinsulating coating of the conductor core by means of an asphalt waterproofing saturant. Recently, however, instead of manufacturing theelectrical conductor with a braided jacket, it has been mam uiacturedwith a knitted loosely woven tubular threaded fabric jacket. The use ofa knitted jacket, and particularly of th character herein set forth, hascertain advantages; namely, rapid production and lower cost. Oneknitting machine can do the work of from six to ten braiding ma chines,and therefore from the standpoint of production capacity, the productionof electrical conductors with knitted jacket is highly advantageous.Further, the use of the knitted jacket, and particularly of thecharacter herein set forth, enables cotton of lower tensile strength tobe used than has hitherto been used in the production of braided tubularprotective fibrous jackets. However, the use of the knitted jacket haspresented quite a problem in that on flexing, bending and twisting ofthe conductor carrying said knitted jacket, said jacket beingimpregnated with the prior art asphalt saturating composition, thethreads of the knitted jacket did not adhere one to the other and didnot adhere sufiiciently to the insulating rubber sheath, which ww justbelow the jacket, to prevent said rubber sheath from being exposed tothe action of the atmosphere, therebycausing rapid deterioration of therubber insulating medium of the conductor core and impairment of theinsulating properties of the con doctor. The apparatus used insaturating the knitted jacket of the conductor core of the presentinvention and in applying the flame proofing stearine pitch and thesubsequent color coating composition is shown inFig. 2. The electricalconductor is provided with a naturallyoccurring or synthetic vulcanizedrubber insulating covering 28 and a tubular jacket 28, as shown inFig.5. This electrical conductor is passed through the saturant 6 present intank 2', the saturant me= dium in said tank being preferably maintainedin the tankat a temperature of about 300 F al through this saturantliquid may vary in temperature between 180 to 350i" El, depending uponthe specific composition of the saturant. The excess saturant medium isremoved from the knitted fabric jacket by means of squeezing rolls 2.There is then applied to the saturated knitted jacket a finishingcoating which may be of any suitable character but which is preferably aflame proofing and a weather proofing coating, as typifled by the priorart coatings of this character, and particularly stearine pitch. Thelatter is applied by means of a wheel is. rotating in a bath of stearinepitch present in the vessel said stearine pitch being preferably heatedto 366 F. The amount of stearine pitch which is applied to the conductoris regulated by the size of the open ing between the rolls to and Whilethe thickness of the stearine pitch coating may vary considerablydepending on circumstances, it is usually between i to 1 thousandths ofan inch thick. It may be somewhat greater or even somewhat less. Taicoran equivalent medium is then applied to the fairly hot stearine pitchcoating from the corn tainer do, said talc serving to diminish the tend:ency of the conductor core to stick to itself when it is wound on the'reel it. The stearine coated conductor core to which the talc has beenapplied is then passed through a polishing device ed aromas vary, theconductor core is preferably passed through these baths at a ratevarying between 200 to 350 feet per minute. The speed of travel is notcritical.

The color coating composition is applied to the conductor in the coatingand drying apparatus shown in Fig. 3, said apparatus comprising anapplicator pot 5 suitably located in a tower 6, said applicator notbeing provided with a partition l whereby there is formed a compartment5 adapted to contain the color coating composition .3 and a wax coatingcompartment adapted to contain a waxing material it. Suitable upper andlower guide rolls it and liars provided, the wire it passing from thepay-off reel it under guide roll it and through the coating solution 3present in the applicator pct t. The wire passes through the coatingcomposition t, through the wiping gasket it, around the upper roll it,then back and down around the lower roll it; then through the coatingcomposition t a second time; and, if

necessary, through the coating composition a thirdtime. Thereafter, thecoated and dried wire passes through the waxing compartment it and thento the re-wind reel El. The tower id is pref: erably, although notnecessarily, an air conditioned chamber. That is, th chamber may becontrolled from the standpoint of temperature and from the standpoint ofhumidity.

The differences in structure between a braided jacket and a knittedtubular jacket will be clearly understood from a consideration of Figs.4. and 5. Referring to Fig. 4, the copper or aluminum wire it carriesthe rubber insulating covering it, and the latter is provided with atubular braided jacket 25. It is to be noted that the thread 22, athread of the right to the left course, passing around the conductorcore, passes under the thread 23 and over the thread of the left to forthe purpose of smoothing and cylindrically,

shaping the conductor core to its final form prior to the application ofthe color coating. The

polishing device is generally water cooled by means of ordinary citywater so that the coatings of the conductor may be, chilled andsolidified at this stage of manufacture. Normally, the saturant tank 2contains about 1000 pounds of saturant, and since the saturating stepand the entire process is preferably a continuous one, the saturant tankis continuously replenished with melted saturant from a preheating tankwhich is preferably maintained at or about-the temperature of the satlll'ullil in the saturant tank. One of th functions of the preheatingtank is to drive ofi from the saturant before the latter is applied tothe knitted jacket, all of the volatile matter that can be driven 0d ata temperature in the neighborhood of 250 to 350 or 400 F. t

It is to be noted that no volatile medium or solveut is present in thesaturant composition. It a volatile solvent were present, such asnaphtha, benzol, alcohol, or the like, it would be necessary 7 to allowthe volatile solvent to evaporate from the saturated knitted jacketbefore the saturant could assumeits final soft and pliable state. Thiswould prohibit rapid manufacture since considerable time would have toelapse between the application of the saturant composition to theknitted tubular jacket, and the application of the finishing coat andits subsequent polishing. While the speed of travel of the conductorcore through the saturant bath and the finishing. bath may the rightcourse, and under thread 25. Thread it of the right to the left coursepasses over thread it, under thread 2t, and over thread The threads ofone course may pass over one thread of the opposite course, under twothreads, then over one thread, and then under two threads. There may beother variations of this over and under structure, but in any case, itis necessary for the threads to pass completely around the conductorcore. Since a braided structure of this type sets comparatively tightlyon the'rubber covered wire, the conductor and the conductor core maybebent and flexed without the braided jacket being so displaced as topermit the exposure of the rubber when, as has been customary, thetubular braided jacket is impregnated with an asphalt saturatingsolution, then covered with a flame proofing stearine pitch, colorcoated, and waxed to produce the well known insulated conductor of theprior art.

Referring to Fig. 5, the wire 27 is provided with a rubber or prior artequivalent insulating covering 2d, the latter being provided with aknitted jacket 29 which is formed of a group of interconnected wales:iii and ti which extend spirally around the wire 2'5 and'the insulatedcovering 28 of the conductor core. The courses 32, 33, 3%. 35, 38 and 37extend longitudinally of the conductor core. In such and similar knittedjackets, the knitting structure being capable of considerable variationso long as the tubular knitted structure is formed of walesextending'spirally around the conductor core, the successive threads ofthe wales having interconnected loops. Each thread, instead of beingwrapped around the conductor core, is laid along it with a loop aroundto the next thread or a second adjoining thread.

However, since the threads are not wrapped around the conductor and arenot bound under or tightly tied to each other, the entire knittedstructure is a relatively loose one, and when the conductor is bent orflexed, the insulating cover of the conductor core, as for example,rubber. pushes through the jacket and is exposed. Stated differently,the fibrous jacket of the prior art was braided, woven or wrapped aroundthe conductor, and each thread of'the Jacket encircled the conductor.The fibrous jacket of the present invention is a knitted jacketcomprising interknitted courses of loops, the separate threads beinglaid along the conductor and not encircling the conductor. The patternof this knit is subject to wide variation depending upon the number ofthread supplies, the number of needles, the dispositionof the needles inthe knitting machine, and the like, and nothing in this disclosure isintended to limit the invention to any one pattern of knitting. for theinvention serves equally :well with any pattern of knitted fibrousjacket.

However, it is desired to point out that the present invention isparticularly suitable for the treatment of knitted jackets as set' forthin Stove! Patents Nos. 2,240,058 and 2,276,523, and the tubular knittedcoverings therein disclosed are by reference made a part of the presentdisclosure so that it may be clearly indicated that thesaturantcomposition of the present invention may be applied to a variety ofknitted jackets, including those formed from a plurality of spirallyextending interconnected wales, the threads of said wales havinginterconnected loops.

.The present invention is directed to the solution of the problempresented by the use of knitted jackets, and particularly those of thecharacter herein set forth, in the production of electrical conductorsand similar articles. It has been ascertained that the exposure of therubber covering to atmospheric influences on the bending, flexing andtwisting of the conductor core in a completed electrical conductor canbe prevented if the tubular knitted jacket is caused to adhere to therubber and the threads of the knitted jacket are caused to adhere toeach other since, when this condition is satisfied, on the electricalconducto and the core being flexed, twisted or bent, the protectiveknitted jacket does not permit the rubber insulating sheath to becomeexposed and therefore impairmentof the insulating properties of therubber sheath and of the electric conductor is prevented.

It is desired to point out that with the introduction of the knittedtubular threaded jacket, the prior art procedure was followed; namely,the fibrous jacket was saturated with asphalt and finished with afinished coating of stearine Ditch. Thereafter, the stearine pitchcoating was pro vided with a color coating, as for example, a cellulosebase compound or an alcoholic soluble gum compound, as is well known inthe art. When this procedure was followed, and an asphaltsaturatingcomposition was used, it was discovered that the asphalt saturant didnot cause the tubular knitted jacket to stick to the insulating sheathwhich it covered, and, further, that the asphalt did not possesssufllcient adhesive properties to cause the threads of the knittedjacket to stick one to the other when the so impregnated electrical corewas bent, flexed and twisted.

After long experimentation, it was ascertained that the electricalconductor and its core' could be bent, flexed and twisted even when itcarried the new knitted tubular protective jacket without exposing theunderlying rubber sheath provided the tubular knitted jacket, andparticularly that of the character herein disclosed, was treated with asaturating medium which would securely attach the loosely-held knittedtubular fabric to the underlying tubular sheath and which would alsofunction to adhesively unite the threads of the tubular knitted jacketone to the other when thetsaturant solidified to an adhesive softpliable s a e.

The knitted jacket, after being treated with the saturant of the presentinvention, then receives a finishing coat which maybe the prior artstearine pitch. Thereafter, the conductor is provided with a color coat.

Broadly stated, the saturating composition may be any material which isa liquid above 130 to 140 F., is capable of penetrating in and throughthe tubular knitted jacket, and on cooling assumes a soft pliableadhesive state, and bonds the tubular knitted jacket to the insulatingsheath underlying it, and, further, bonds the threads of the knittedjacket one to the other, all in such a manner that when the conductorand its core is bent, flexed and/or twisted, the underlying insulatingsheath will not be exposed to atmospheric influence. The saturatingcomposition, when in a liquid or molten state, penetrates into thethreads 0! the knitted tubular jacket and through the threads so thatthe jacket and individual portions thereof will be held over its entireunder surface to the upper surface of the rubber insulating sheath, orthe two will be held together by spots of adhesive in a, manner similarto the spot welding of one metal to another. When the saturant iscooled, it possesses, at room temperature, adhesive properties whichtend to bind the tubular knitted jacket to the rubber insulating sheath,and tend to bind the threads of the jacket one to the other.

The saturant base of the saturant composition is applied to the tubularknitted jacket by immersing or passing the conductor core through abathof the saturant composition which is maintained in a thin fluid state.Naturally, the

temperature necessary to maintain the saturant in this condition willvary, but usually it varies between 260 to 350 F., but may be as low as180 F. It is desirable to keep the impregnating temperature of 'thesaturant composition as low as possible consistent with a liquid statebecause at elevated temperatures, the rubber insulatin sheath or otherinsulating medium may be slightly damaged. The saturating compositionshould be sufliciently liquid to penetrate the knitted jacket whilehaving no deleterious effect on the insulating sheath, which ispreferably rubber, but which, as pointed out, may be any other prior artmaterial having insulating properties, and with the shortage of rubber,any of the equivalents of rubber may be used. The saturant compositioncools from a temperature range of between 260 to 300 F. to a soft,pliable state characterized by the property, in its solid state, ofcausing the fibrous sheath to adhere to the rubber insulator and thevarious threads of the sheath to adhere one to the other.

The saturant composition may have as its saturant base a natural orsynthetic gum or resin, acellulose ester or ether, chlorinated rubber,and the like, provided these materials have suflicient plasticity sothat upon cooling from the temperature of application to normal roomtemperature or thereabcuts, the composition not only acts as an adhesivein the mannerset forth, but is also sufllclently soft and pliable topermit the elecknitted tubular jacket to separate from each other. Ifthe saturant-base does not possess sumcient plasticity to function asspecified, then there is added to the saturant composition aplasticlzer, which term as herein used includes the vegetable oils. Thecomposite saturant composition will then possess the proper physicalcharacterlstics which will enable it to set to a soft and pliable state.

It has been ascertained that particularly satisfactory results can beproduced by using natural gums or natural or synthetic resins. Among thenatural resins which may be used are rosin, .Pontianac, Manila gum,kauri, Congo, sandarac, shellac, dammar, ester gum, lime hardened rosin,and the like. Among the synthetic resins which may be used are thephenol aldehyde condensa= tion products, including phenol formaldehydecondensation products, furiural condensation resins, urea and thioureaaldehyde condensation products includingurea and thioureaformaldehyde'products, and alkyd resins including the glyptals. Thealkyd resins constitute thecondensation product of a polyhydric alcoholand a poly basic acid. The g yptal resin is an example of an alkydresin, said glyptal resin being a. condensation productof glycerol andphthalic anhvdrlde. Benzyl and styrene resins may be used, said resinsbeing produced by polymerizing styrene or benzyl benzene. These resins,in many of their forms, are clear and colorless. Chlorinated rubberknown under the trade name of Pliofihn, synthetic rubber compositions,and Paracoumarone-indene resins may also be used.

Acrolein and acrylic acid resins which are on the market under the tradename of Lucite-znay also be used. Few of the gums or esters formsufilciently plastic adhesives to be used without the addition of anagent acting as plasticizer and imparting to or augmenting the adhesiveproper- Esomple 1 J her cent Ester 8 Soya bean ni 2.8

Emmple 2 Per cent Paracoumarone-indene resin- 86.3 Menhaden 11 16.?Example 3 Per cent Asphalt $1.2 Paracoumarone-indene resin 15A Cottonseed oil 23% Example 4 i Per cent Ethyl cellulose bl Soya bear oil asEoompie 5 Per cent Lime. hardened rosin so Ethyl cellulose Castor oil 29Example 6 Per cent Phenol formaldehyde resin l3 Linseed oil 25Anti-oxidant 2 Example EPer cent Alkyd resin 37 Petroleum oil b Ester ofphthallc acid i 4.

Example 8 Per cent Manila gum d7 Tricresyl phosphate 23 Example 9 Percent Shellac 5:3 Urea formaldehyde resin 31 Dibutyl phthalate l5 ties ofthe saturant. For example, it has been i found that while'ester gum maybe used as a base of the saturating compound, it is highly desirable toadd thereto a material which will increase the adhesive propertiesthereof and plasticize it. Such a material, is the mineral, vegetable,or animal oil. Among the oils which may be combined with the ester gumor similar base are petroleum derivatives including lubricating oil,parafiln, vegetable oil such as castor oil, linseed oil, soya bean oil,corn oil, China-wood oil, oiticica oil, cocoanut oil, rapeseed oil, andthe like. Fish oil is a representative of a suitable animal oil. Theplasticizing and adhesive increasing agent may also be organiccompounds, as, for example, esters of phosphoric acid or esters ofphthalic acid. The chlorinated polynuclear aromatic hydrocarbons alsofunction well in the above capacity.

asonear From the standpoint of expense, ester is the most desirablesaturant base to use and in order to plasticize the'gum, it is desirablethat there be present in the satu'rant composition a suitableplasticizer. The vegetable oils, and particularly soya bean oil, havegiven very satisfactory results. The ester gum may be produced bymelting ordinary resin in a kettle with the required amount ofglycerine. The molten ester gum may be allowed to cool, or, if desired,the saturant composition may be produced by adding to the molten estergum a plasticizing constituent which also preferably imparts to thesaturant composition adhesive properties. The acid number of the estergum used in carrying out the present invention is not critical; it maybe low or high, but the physical hardness or brittleness i of the estergum determines the kind and amount g It is quite desirable that thesaturant compo- The following are examples of suitable saturantcompositions:

The saturant may solidify to a sticky of plasticizer which may beinstead of using ester gum, rosin itself, or lime hardened rosin may beused. While the plasticizing-constituent of the saturant composition ispreferably a non-drying or semi-drying oil so that the compositesaturant composition will not lose its salt pliable adhesive conditionafter being applied to the knitted jacket, a drying, oil may be used, asfor example, linseed oil or China-wow 011 provided an anti-oxidant ispresent in the saturant composition to substantially prevent or inhibitoxidaticnoi the r 1. oil. It is desirable used. In some cases,

The ethyl cellulose ether is used because this derivative is easily andreadily available and, further, it forms a tougher and harder film thanany of the other cellulose ethers. It has a very low burning rate and isfree from discoloration from sunlight. The ethyl ether set forth inExample 4 may be replaced in whole or in part by any one or a mixture ofthermoplastic cellulose ethers having the properties above set forth.These cellulose ethers include propyl cellulose, butyl cellulose, benzolcellulose, ethyl benzol cellulose, ethyl propyl cellulose, methy butylcellulose, and the like. The term thermoplastic cellulose ether" isintended to designate those cellulose ethers which at room temperatureand slightly above are solid and which melt tb a liquid at elevatedtemperatures. The saturant composition may contain a gum or resin inconjunction with a cellulose ether of the kind above referred to, andespecially ethyl cellulose. As indicated in Example 5, the saturant basecontains a predominating quantity of a resin; namely, a

lime hardened rosin, and a relatively small proportion of a celluloseether. However, it is not intended to limit the invention to a saturantbase in which the resin predominates over the cellulose ether. Thereverse may be true, and the cellulose ether predominate over the resin.Where necessary, the plasticizer may be present in the saturantcomposition in an amount varying between 2% to about 50% based on theweight of the composite saturant composition. The plasticizers arepresent in the respective examples in the following amounts: Example 1,23%; Example 2, 17%; Example 3, 23%; Example 4, 46%; Example 5, 29%;Example 6, 25%; Example 7, 13%; Example 8, 13%; and Example 9, 15%.

The saturant base as shown in Example 9 may consist of a natural resinillustrated by shellac and a synthetic resin illustrated by a ureaformaldehyde resin. Obviously, for the shellac, other natural resins maybe substituted, and other synthetic resins may be substituted for theurea formaldehyde resin.

Referring to Example 7, it is to be noted that the saturant basecomprises an alkyd resin, the term alkyd designating a well known typeof resin. It is within the province of the present invention to mix thealkyd resin with a cellulose ether of the type herein described, thelatter being present in a predominating proportion or the alkyd resinbeing present in a predominating proportion and the cellulose etherpresent in a minor proportion.

Th examples given are merely illustrative of saturant compositions whichmay :be used to carry out the invention. Having once pointed out theproblem to be solved and its solution, those skilled in the art will beable to formulate equivalent saturant compositions for filling the basicrequirements herein set forth.

The proportions set forth in the above ex amples are by way ofillustration and not by way of limitation. The various ingredients maybe varied considerably and still come within the spirit of the presentinvention. The physical characteristics of the saturant; namely, itsductility, its tensile strength, its adhesiveness, its ability topenetrate into and through the knitted fabric Jacket, its capacity toretain these characteristics for a considerable period oftime, itsthermal nature including its liquidity at above 130 F. and its abilityto be maintained in a solid state at temperatures below 130 F., are thefactors which determine the usefulness of the saturant base in carryingout the present invention, and therefore any combination of materialswhich possesses the properties herein set forth including gums, resinsand cellulose ethers with or without a plasticizer such as oil or thoseof the character set forth in the examples, may be satisfactorily used.

The stearin pitch which may be used as the finishing coat to be appliedover the knitted jacket which has been saturated with the abovedisclosed saturant composition, typifies the residue which remains inthe retorts from which it is distilled by vacuum distillation, such freefatty acids as stearic, palmitic, oleic, myristic, and the like, such asmay be obtained from oleo stearine, lard, oil, cotton seed, soya beanoil, corn oil, and the like, after said materials have been hydrolyzedfor the recovery of their glycerol content. This residual pitch is asolid, jet black in color, containing free carbon in suspension,

- and is a highly polymerized condensed residue of a rubbery-likenature, which becomes tacky and flows at slightly elevated temperatures.

of course. such a material may be mixed with asphalt or wax, or withboth or these ingredients may be copper, or aluminum, or any otherelectrical conductive wire, any equivalents of the rubber may be usedprovided the equivalent material has comparable insulating properties.Naturally, the synthetic vulcanizable rubbers may be used, as, forexample, that derived from butadiene, isoprene, dimethyl butadiene, orother homologs or analogs of butadiene.

It is desired to point out that any suitable color coating compositionmay .be applied over the finishing coat. Examples of satisfactory colorcoating compositions are as follows:

, Table 3 s Per cent Metallic red oxideu 21.5 Filmscrap or cellulosenitrate 8.? Shellac 1.2- Acetone 61.08 Methyl alcohol 1.4;,1 Beta nap.16

Table 4 Per cent American whi in 9.65 Ashestine 5.60 Red iron oxide La15.30 Filmscrap 7.15 Alkvd res 3.28 Aluminum stearate 9.87 Betanaphi-hnl @995 Hydrogenated petroleum iraction 7.95

Acetone 50.19?

Table 5 Per cent Titanium di 871i Ferric oxide yellow 1.88 Lea-d chr 7.08 Red iron oxide" 1.25,

ll ilmscrap 5716 Alkyd resin 3.98 'lvialeic .ahhydride resin 2.475 Blowncastor oil 1.88

Methyl acetate 33.49 Methyl alcohol 5.91 Beta n h hn 0.005

While the stearine pitch coating may be used as the finishing coat, thetubular knitted jacket carrying the saturant herein disclosed may beflexed and/or twisted, said basic material having r a primary coveringtherefor and a knitted jacket of any shape covering said primarycovering, said jacket being formed of interconnected wales, thesuccessive threads of said wales having interconnected loops. Theknitted jacket may be impreg-= nated with the soft pliable adhesivesaturant composition herein set forth to adhesively unite the knittedjacket to the primary covering and to also adhesively unite the threadsof the jacket together so that upon bending and/or flexing and/ortwisting of the base material, the primary covering,

irrespective of whether or not it has insulating properties, is notexposed to deteriorating atmospheric influence.

Having thus described the invention, what is claimed as new and desiredto be secured by Let ters Patent is: v

1'. The method of manufacturing an electrical conductor having aconductor wire, an insulating jacket thereon, and therecver a tubularknitted protective jacket comprising heating a saturant to substantiallyremove therefrom all volatile matter, impregnating said knitted jacketwith said saturant and adhesively uniting the knitted jacket to theinsulating jacket while adhesively uniting the threads oi the lmittedjacket together While the invention is of particular.

accuser 7 so that upon subjecting the so-treated conductor tosubstantial stresses the insulating jacket is not exposed todeteriorating atmospheric conditions. 2. The method of manufacturing anelectrical conductor having a conductor wire, an insulating jacketthereon, and thereover a tubular knitted protective jacket comprisingheating a plastic resin saturant to substantially remove therefrom allvolatile matter, impregnating said knitted jacket with said saturant andadhesively uniting the knitted jacket to the insulating jacket whileadheslvely uniting the threads of the hiitted jacket together so thatupon subjecting the sotreated conductor to substantial stresses the insulating jacket is not exposed to deteriorating atmospheric conditions.

3. The method of manufacturing an electrical.

conductor having a conductor wire, an insulating jacket thereon, andthereover a tubular mitted protective jacket comprising heating asaturant to substantially remove therefrom all volatile com= ponents,maintaining the so-treated saturant at a temperaturevarying between 180F. to 350 lid, impregnating said knitted jacket with said heatedsaturant free or volatile components and adhe= sively uniting theknitted jacket to the insulating jacket while adhesively uniting thethreads of theknitted jacket together so that upon subjecting theso-treated conductor .to substantial stresses the insulating jacket isnot exposed to deteriorating atmospheric conditions.

i. The method or manufacturing an electrical conductor having aconductor wire, an insulating jacket thereon, and thereover a tubularknitted protective acket comprising heating a plastic resin saturant tosubstantially remove therefrom all volatile components, maintaining thesotreated saturant at a temperature varying between 180 F. to 350 ii,impregnating said knitted jacket with said plastic resin saturant freeof volatile components and adhesiveiy unit= ing the knitted jacketto-the insulating jacket while adhesively uniting the threads of theknitted jacket together so that upon subjecting I hesively uniting thethreads of the-knitted jacket together so that upon subjecting theso-treated conductor to substantial stresses the insulating jacket isnot exposed to deteriorating atmospheric conditions.

6. The method of manufacturing an electrical conductor having aconductor wire, an insulating jacket thereon, and thereover a tubularknitted protective jacket comprising treating said knitted jacket with asaturant containing a resin and a thermoplastic cellulose ethercompatible with said resin, said saturant being sufiioiently liquid topenetrate the knitted jacket while exerting little deleterious efiect onthe insulating jacket thereunder and adhesively uniting the knittedjacket to the insulating jacket while adhesively uniting the threads ofthe hitted jacket together so that upon subjecting the so-treatedconductor to stresses the insulating jacket is not exposed todeteriorating atmospheric conditions, and applying a flame-proofingcoating to the so-treated knitted jacket.

7. The method of conductor having a. conducting core, comprisingapplying directly to saidcore a vulcanized rubber insulating jacket andapplying directly over said insulating Jacket a single relatively looseknitted tubular jacket only, impregnating-said knitted jacket with a hotnon-vulcanizable liquid adhesive maintained at a temperaturevaryingbemanufacturing an electrical tween 180 and 350' F. and which "aby cooling only to a soft pliable solid' adhesive state and in its setstate has sumcient adhesiveness to adhesively unite the threads of theknitted jacket together and hold the knitted'jacket in adhesive contactwith the insulating Jacket to prevent the latter from being exposed todeteriorating atmospheric influences upon bending flexing and twistingof the conductor, and directly cooling the so-

